Diesel engines are used in a wide variety of industrial applications. These engines are known as compression ignition engines because they are internal combustion engines that utilize the heat of compression to ignite the diesel fuel in the combustion chamber of the engine.
Many industrial applications where diesel engines are used would benefit environmentally and economically from use of natural gas as the engine fuel. Natural gas is generally readily available, tends to be more economical and produces less undesirable emissions when burned. Furthermore, engines burning natural gas generally may have fewer maintenance problems. However, the ignition of natural gas in compression ignition engines may be difficult because natural gas has a much higher temperature for auto ignition than diesel fuel. To resolve this problem a small amount of pilot fuel, such as diesel fuel, may be used to start ignition of the primary fuel, natural gas, in the combustion chamber of the engine.
Detection of high and low natural gas pressures in the gas rail may be beneficial for engine performance. Overly high gas pressures may be a factor in engine injectors misfiring and may lead to premature component wear. Overly low gas pressures may result in low engine power. Similarly, detection of high and low natural gas pressures in the gas system upstream of the gas rail may be beneficial to engine performance since overly high gas pressures may wear or damage filters or seals, and overly low gas pressure may result in low gas pressure in the gas rail and low engine power.
U.S. Pat. No. 7,100,574 discloses technology for detecting an abnormality in a pressure on an inlet side of a supply pump or an inlet side of a high-pressure pump included in the supply pump. If the inlet pressure is outside of a predetermined range for a predetermined period of time, the system determines that the pressure is abnormal. While this system may help reduce the false detection of abnormality due to system noise, the system has drawbacks because the system overlooks pressure deviations that do not last longer than the predetermined range. A design is needed for the detection of high and low gas pressures in the gas rail and in the gas system.